code: def test_pdf_has_roots(self):
      with warnings.catch_warnings():
          warnings.simplefilter("error", RuntimeWarning)
          assert_raises(RuntimeWarning, ExpandedNormal, [0, 1, 101])
  
imports: import warnings
  import numpy
  from numpy.testing import assert_equal, assert_raises, assert_allclose
  import numpy.testing
  from scipy.special import gamma, factorial, factorial2
  import scipy.stats
  from statsmodels.distributions.edgeworth import _faa_di_bruno_partitions, cumulant_from_moments, ExpandedNormal
label_desc: Use image node_id 6 for calling the TestExpandedNormal obj's underlying member method code with example usage: obj.test_pdf_has_roots() without return types